Existing systems are currently encountering technical problems.
In the case of rigid thick profiles, the wing surface is difficult to modify.
Semi-rigid thick profiles use relatively complex mechanical systems which very often require special rigging (mast with several sail feeders) which do not always allow a reduction in sail area and stowage and which do not produce the intended effect of a thick sail (combination of two sails with issues surrounding retention of the thickness of the sail, for example). Patents FR 2 431 425 and FR 2 401 059 describe interesting semi-rigid thick profiles but the proposed devices are permanent and often require the creation of a new sail.
The applicant in patent FR 2 955 830 has likewise proposed detachable thickness modules for constructing a sail with an aircraft wing profile from a traditional flexible sail, one or several modules being capable of being assembled in a detachable manner on a face of the flexible sail. The modules are formed from one or several three-dimensional members assembled on the flexible sail.